Check out Luta Livre as well. A number of good vale tudo fighters come from a LL background.

Also, the bit about BJJ/LL rivalry is apparently true. There was a fight between Renzo Gracie (BJJ) and Eugenio Tadeu (LL) in '97 that got stopped when the BJJ and LL fans got into a huge fight. I think they pretty much put it behind them these days though.